What it is
ThermoCycleDesigner provides an interactive, end‑to‑end assessment of a simple Rankine steam cycle for mechanical and thermal engineers. By supplying the enthalpy values at the key states (liquid before pump, pump outlet, vapor after boiler), component efficiencies and mass flow rate, it computes the mechanical work delivered to the load and the overall thermodynamic efficiency. The calculations follow standard engineering practice: pump work is corrected by its isentropic efficiency; turbine work uses the actual efficiency applied to the ideal enthalpy drop between high‑pressure vapor and low‑pressure liquid; heat added in the boiler is the enthalpy rise from pump outlet to boiler exit. These results enable rapid comparison of cycle designs, assessment of component performance, and identification of limiting stages.
Temperature readings are echoed for reference so users can check operating ranges against design specifications or regulatory limits. The calculator therefore delivers both quantitative performance data and contextual temperature information in one place, surpassing static educational resources that merely present formulas.
How to use it
Enter the enthalpy of the liquid entering the pump (often the saturated liquid at condenser pressure) in kJ/kg. Provide the enthalpy after the boiler (high‑pressure vapor). Specify the actual enthalpy after pumping; this is usually close to the liquid value at high pressure. Input the isentropic efficiencies for both pump and turbine as fractions between 0 and 1. Enter the total mass flow rate through the cycle in kg/s. Type the evaporator inlet temperature, condenser inlet temperature, and condenser outlet temperature in Kelvin if you wish to review them.
After clicking “Calculate,” the tool displays the net mechanical power output in kW and the overall thermal efficiency as a percentage, both rounded to two decimals for clarity. The temperatures are shown unchanged for your reference.
Worked example
1. Pump work per kg is the enthalpy rise divided by pump efficiency: w_pump = (200 – 191.8) / 0.85 ≈ 9.65 kJ/kg. 2. Ideal turbine work per kg comes from the high‑pressure vapor dropping to the low‑pressure liquid: wt_ideal = 2765 – 191.8 ≈ 2573.2 kJ/kg. 3. Apply turbine efficiency: w_turbine = 0.88 × 2573.2 ≈ 2265.14 kJ/kg. 4. Heat added in boiler per kg: q_in = 2765 – 200 = 2565 kJ/kg. 5. Net specific work: w_net_specific = 2265.14 – 9.65 ≈ 2255.49 kJ/kg. 6. Net power output: 10 kg/s × 2255.49 kJ/kg ≈ 22547.69 kW. 7. Overall efficiency: (2255.49 / 2565) × 100 ≈ 87.91 %. 8. Temperatures are reported exactly as entered for reference.
Inputs
- Saturated liquid enthalpy at low pressure (kJ/kg): 191.8
- Vapor enthalpy after boiler (kJ/kg): 2765
- Pump outlet enthalpy (kJ/kg): 200
- Pump isentropic efficiency: 0.85
- Turbine isentropic efficiency: 0.88
- Mass flow rate through cycle (kg/s): 10
- Evaporator inlet temperature (K): 263
- Condenser inlet temperature (K): 373
- Condenser outlet temperature (K): 298
Result
- Net power output (kW): 22547.69
- Overall thermal efficiency (%): 87.91
- Evaporator inlet temperature (K): 263
- Condenser outlet temperature (K): 298
Frequently asked questions
What if my cycle has more than two boiler stages or multiple turbines?
This tool is designed for a single‑stage Rankine configuration. For multi‑stage designs, compute each stage separately and sum the works; then feed the aggregate values into the calculator as if they were from a single equivalent stage.
How accurate are the enthalpy inputs I must supply?
The accuracy of the results follows directly from your enthalpy data. If you use standard steam tables or an advanced property package, the outputs will be highly reliable. For quick estimates, using typical saturated liquid/vapor values yields acceptable engineering order‑of‑magnitude insight.